Russian aircraft have reportedly staged air strikes in northern Syria in support of a Turkish offensive against ISIS, marking the latest attempt at mending relations between the two governments. Russian-Turkish relations have been strained since a Turkish fighter shot down a Russian strike aircraft flying out of Syria that had strayed into Turkish air space in November 2015.https://www.nytimes.com/2017/01/08/us/politics/russia-turkey-syria-airstrikes-isis.html?_r=0